Jackets with front zippered or welted pockets that slant at an angle are visually flattering. That’s because the slant of the diagonal lines draws the eye inward to give the illusion of a narrower waist. The angle of the pockets can slant upwards or downwards to create the same “narrowing effect”. And some slope at a steeper incline than others. The examples here illustrate the point quite well.

Sejour Jetsetter Ottoman Knit Jacket

Welted or zippered pockets that are positioned horizontally or vertically close to the waist don’t have quite the same narrowing effect because those lines draw the eye across or down (not inward). Both my Smythe equestrian jackets have steep slanting front welted pockets that make my waist appear narrower than it is. 

It’s not at all essential for jackets to have this design feature, but it might be worth considering when you want to create the illusion of a more defined waist. Many of my rectangular and apple shaped clients enjoy the subtle design feature because it gives their waistline more definition. Some of my curvy clients enjoy it because it accentuates their already well-defined waist.